This application corresponds to Japanese Patent Application No. 9-183740, filed on Jul. 9, 1997, which is hereby incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a flyback transformer which is used in a television receiver and other devices, and more particularly, to the structure of an anode lead wire used for connecting the flyback transformer and a cathode ray tube (CRT).
2. Description of the Related Art
Hitherto, flyback transformers have been installed in television receivers or display apparatuses. In such an application, a high output voltage is applied from high-tension coils (e.g., secondary coils) used in the flyback transformers to anodes used in cathode ray tubes through anode lead wires. In recent years, a so-called anode-lead-wire-post-mounting technique has become prevalent as a step in the assembly of television receivers and like display apparatuses. In this process, the anode lead wire is mounted to the flyback transformer after the flyback transformer has been installed in the television receiver or display apparatus so as to facilitate assembly.
FIG. 6 shows the connection mechanism of an anode lead wire in a conventional flyback transformer produced by the above-described technique of anode-lead-wire-post-mounting. The connection mechanism used to connect the anode lead wire 51 is mainly composed of the anode lead wire 51, an anode lead holder 52 and a conductive rubber member 53 (e.g., conductive rubber member 53 may comprise rubber or other resilient material with conductive material added thereto). The anode lead holder 52 is formed in a cylindrical shape and is made of an insulating resin material. The anode lead holder 52 has engagement pieces 54 having resilient properties when extended in an inward (radial) direction. The engagement pieces 54 project from the inner surface of the anode lead holder 52. The anode lead wire 51 is inserted from one opening (the right end in FIG. 6) of the anode lead holder 52, and the conductive rubber 53 is pressed into the other opening (the left end in FIG. 6) and fixed thereto. A high-voltage lead wire 58 for providing a high voltage output from a high-tension coil (e.g., a secondary coil) is thrust into the conductive rubber 53. The inner diameter xe2x80x9cbxe2x80x9d of the anode lead holder 52 is defined by the size of a connecting fitting 57 mounted to the head of the anode lead wire 51.
As shown in FIG. 7, an insulating film 55 at the head of the anode lead wire 51 is removed to expose a core wire 56. In addition, a metal connecting fitting 57 is attached to the head. To attach the connecting fitting 57 to the anode lead wire 51, the edges of the connecting fitting are tapered so that they cut into and engage the insulting film 55. Also, the core wire 56 and connecting fitting 57 are secured by solder 59.
A series of operations used to secure the anode lead holder 52 to the anode lead wire 51 will now be described. The anode lead wire 51 having the connecting fitting 57 attached to the head thereof is first inserted from one opening (e.g., the right opening) of the anode lead holder 52. When the connecting fitting 57 engages the engagement pieces 54, the connecting fitting 57 is advanced so as to gradually expand the space between the tips of the engagement pieces 54, and the head of the core wire 56 is thrust into the conductive rubber 53. When the connecting fitting 57 is advanced such that the portion thereof which cuts into the insulating film 55 passes the tips of the engagement pieces 54, the engagement pieces 54 return to their original state as a result of the elastic restoring force thereof. In this state, the engagement of the connecting fitting 57 with the engagement pieces 54 allows the anode lead wire 51 to be retained. That is, the engagement pieces 54 thereby prevent the anode lead wire 51 from falling out, so that the anode lead wire 51 is held and fixed to the anode lead holder 52.
The conventional flyback transformer encounters at least the following problems.
The connecting fitting 57 is required to be attached to the head of the anode lead wire 51, so that the number of components is increased and the operation of mounting the connecting fitting 57 requires much labor, resulting in an increase in cost.
In addition, it is necessary to widen the inner diameter xe2x80x9cbxe2x80x9d of the anode lead holder 52 to accommodate the relatively large size of the connecting fitting 57, resulting in an increase in size of the anode lead holder 52.
Accordingly, it is an object of the present invention to provide a flyback transformer in which the head of the anode lead wire can be easily processed, and in which the connection mechanism for connecting the anode lead wire to the anode lead holder can be reduced in size.
According to an exemplary aspect of the present invention, there is provided a flyback transformer including a transformer section including a magnetic core incorporated into a coil. An anode lead wire is composed of a core wire and an insulating film for covering the core wire. The anode lead wire is used for supplying a high output voltage generated in the transformer section to a CRT. A cylindrical anode lead holding means is provided which has at least one engagement piece which is elastic in at least the radial inward direction of the anode lead holding means. The at least one engagement piece projects from the inner surface of the anode lead holding means and holds the anode lead wire. The anode lead wire has a groove formed on a part of or around the whole circumference of the insulating film. The groove engages with the at least one engagement piece, whereby the anode lead wire is securely held by the anode lead holding means.
According to another exemplary aspect of the present invention, there is provided a flyback transformer including a transformer section formed by a magnetic core incorporated into a low-tension coil part and a high-tension coil part. The anode lead wire is composed of a core wire and an insulating film for covering the core wire and for supplying a high output voltage generated in the transformer section to a CRT. A cylindrical anode lead holder is provided having at least one engagement piece which is elastic in at least the radial direction of the anode lead holder. The at least one engagement piece projects from the inner surface of the anode lead holder and holds the anode lead wire. A conductive rubber member is provided on a high voltage extraction portion of the transformer section and is electrically connected to the core wire of the anode lead wire. The anode lead wire has a groove formed on a part of or around the whole circumference of the insulating film. The groove engages with the at least one engagement piece, whereby the anode lead wire is held by the anode lead holder.
With the described arrangements, by only partially removing the insulating film of the anode lead wire to form the groove, without attaching a connecting fitting to the head of the anode lead wire, the anode lead wire can be fixed to the anode lead holder without incurring the disadvantages discussed above.